Management of various cardiac and pulmonary diseases is made exceedingly difficult by the lack of quantitative pressure and flow data. Reliable right heart pressures cannot be made noninvasively. The long term objective of the proposed activity is aimed specifically at noninvasive right heart pressure measurements. To accomplish this, tiny microbubbles will be injected and insonated ultrasonically upon entering the area where data are needed. The resonant frequency of the bubble is a direct measure of chamber pressure. Such bubbles do not now exist. The technological innovation that must be established in Phase I is to create nondissolving gas microbubbles. This will be done by forming gas micelles. Candidate micelle substances will be thoroughly examined. Phase II efforts will be directed at producing the precision needed for the technology and the continuation of the development supported earlier by NHLBI. The concept will produce pressure time histories in both right heart chambers and the pulmonary artery. Once the rudiments of the technology are known, smaller micelles could be produced which could traverse the lungs for left heart pressure measurements. Potentially, this cost competitive concept could have significant commercial value since many millions of measurements are required annually.